An example of conventional keyboard tilting mechanism is constructed such that leg members for adjusting the angle of a keyboard are provided rotatably to a keyboard body, the leg members are forced to move in one direction along the direction and axis of the rotation by a coil spring wound on to the axis of the rotation of the leg members, and the force of said coil spring along the direction of the rotation to the leg members is prevented and released. Such a conventional mechanism is described in Japanese Pat. No. 59-113355, 59-100331, and 60-140134. However, such a conventional mechanism is provided with different members for manipulation from the leg members in order to prevent or release the force of said coil spring. Thus its construction is complex, its assembly is difficult, and its operation is inconvenient. Besides, if different members for manipulation from the leg members project, for example, from the side of a keyboard body, they are inconvenient for storage and conveyance, especially, for a notebook computer and the like.